Airplane propeller



M. E. SMR-TH 1 911 19 332 AIRPLANE PROPELLER Filed May 1'7, 1932 Patented June 13, 1933 UNITED STATES PATENT OFFICE MABCELLUS EUGENE SMITH, F LOS ANGELES, CALIFORNIA, ASSIGNOR 0F ONE-EIGHTH TO DALE D. ZHALE, OF L08 ANGEL-ES, CALIFORNIA, AND ONE-EIGHTH TO RAY M.

HALE, or LAS VEGAS, NEVADA AIRPLANE PROPELLER Application filed May 17,

This inyention relates to a propeller and more particularly pertains to a propeller of the spiral or helical blade type.

An object of the invention is to provide a propeller embodying a construction whereby the fluid in the zone acted on by the propeller blades will be densified relative to surrounding fluid as the propeller advances thereinto, and to provide a form and arrangement of a plurality of propeller blades whereby the blades on being rotated will advance spirally into the densified zone of fluid and each blade present an efiective operating surface throughout a distance of at least onehalf a convolution.

Another object is to provide a propeller of the above character in which the spirally disposed blades may be adjusted to vary their spiral pitch, and embodying a construction whereby corresponding adjustment of a plurality of the blades may be efiected to in-= sure cooperating blades having equal pitch in the various adjusted positions.

Another object is to provide an effective means for securely retaining the blades in a fixed position relative to a cylinder and in their adjusted positions to insure against accidental displacement thereof.

Another object is to provide a propeller which is so formed that when advancing into the fluid the pressures generated thereby will serve to assist in edecting rotation of the proeller.

p Another object is to provide a propeller which is particularly advantageous for use in the propulsion of air craft, and which is especially adapted for operation at high speeds, with the employment of a minimum of mechanical power.

Another object is to provide a propeller oi? the spiral type embodying a construction whereby helical blades may be disposed at various spiral arrangements around a cylindcr without the formation of gaps between the outer periphery of the cylinder and contiguous portions of the blades.

With the foregoing objects in View, together with such other objects and advanta gcs as may subsequently appear, the invention resides in the parts, and in the combi- 1932. Serial No. 611,781.

nation, construction and arrangement of parts hereinafter described and claimed and illustrated by way of example in the accompanymg drawing, in which:

Fig. 1 1s a view of the propeller as seen in front elevation;

2 is a view in side elevation;

, Flg. 3 1s a view in lon itudinal section taken on the line 3-3 of Fig. 1-;

F 1g. 4; is a view in cross section as seen on line 44 of Fig. 3;

Fig. 5 is a viewin section and elevation as seen on the line 55 of Fig. 3;

Fig. 6 is a detail in section taken on the line 66 of Fig. 4, with parts shown in plan.

Referring to the drawing more specifically, A indicates the propeller generally, which Blllbodies a hollow cylinder B from the outer periphery of which projects at least a pair of blades 10 and 11 each of which extends spirally around at least half the circumference of the cylinder, each of the blades thus being approximately a half convolution in length; the blades 10 and 11 extending from opposed halves of the cylinder at opposite inclinations with their adjacent ends spaced apart and slightly overlapping each other. The outer edges of the blades are formed on arcs concentric with the axis of the cylinder so as to collectively present anannular wall around the cylinder. The protruding portions of the blades are tapered in cross section, as shown in Fig. 3, and the leading or entrant ends of the blades are curved outwardly, as indicated at 12, while the trailing ends are curved rearwardly away from the back of the ad'acent leading end of the other blade, as indicated at 13.

The cylinder B is composed of a pair of annular walls i l and 15 which are spaced apart to form a slot C circumferentially of the cylinder B through which the blades extend, the walls ll and 15 being detachably secured to flanges 16 and 17 formed on plates 18 and 19 as by screws 20 and 21. A drive shaft D extends axially of the cylinder B and has a tapered outer end portion on which is mounted a hub 22 carrying the plates 18 and 19 which latter are spaced apart. The outer end of the shaft is formed with a threaded ill stem 23 on which is screwed a nut 2 1 whereby the hub is clamped on the shaft in engagement with a key 25 on the latter. The cylinder is thus aflixed to the shaft to rotate therewith. Projecting diametrically from the hub 22 are axially aligned trunnions 26 and 27 on which the blades 10 and 11 are pivotally carried at the longitudinal centers thereof, whereby the blades may be'turned to extend diagonally through the slot C at various angles so that the pitch of the blades maybe varied as occasion may require.

Means are provided for collectively shifting the blades around. their pivotal connection with the trunnions, which means is here shown as comprising a screw E revolubly carried by the plates 18 and 19 and extending through sleeves 28 and 29 pivotally supported in openings 30 and 31 formed on overlying inner end portions of the blades 10 and 11; the sleeves being carried on pivots 32. The screw E is formed with correspondingly pitched right and left threads ,33 and 34 at its opposite end portions, engaging the sleeves 28 and 29 so that on turning the screw the adjacent overlying ends .of the blades 10 and 11 will be moved in opposite directions. A head 35 is formed on one end of the screw E and is arranged forward .of the plate 18 whereby the screw may be engaged by a suitable tool and rotated thereby to effect adjustment of the blades. The screw E is held against longitudinal movement relative to the plate 18 by the head 35 and a collar 36 which latter abuts against. the inner face of the plate 18.

As a means for securely holding the blades in their adjusted position a series of bolts 37 and 38 are screwed through the plates 18 and 19- to abut against the opposite sides of the inner portions of the blades; the'bolts being advanced or retracted as need be either to permit swinging movement of the blades or to clamp the blades against movement.

As a means for maintaining the slot C closed, the blades 10 and 11 are fitted with laterally projecting flanges 39 and 40 which underlie the adjacent margins of the rings 14 and 15 in sliding contact therewith, the outer faces of which flanges are formed on a segment of a sphere whereby on swinging the blades on the trunnions to various positions the outer faces of the flanges will at all times abut against the inner faces of the rings; the arcuate outer surfaces-of the flanges extending concentric with the point of intersection of the axis of the cylinder B with the axis of the trunnions 26 and 27.

Mounted on the forward end of the cylinderB is a cone F which is demountably attached to the cylinder-as by screws 42 and which cone constitutes a fairway and serves on'advance of the propeller into a fluid to displace the fluid and thereby form a densified zone of the fluid on which the blades act.

The shaft D extends rearwardly of the cylinder B and connects with a suitable motor (not shown) in a usual manner, and encompassing the shaft is a drum G having an outside diameter substantially corresponding to that of the cylinder, and which drum leads rearwardly from the back-end of the cylinder B any suitable distance'to the motor supporting structure.

In the operation of the invention the blades 10 and 11 are disposed in their desired angular relation to each other by means of the screw E as before described; swinging of the blades on the trunnions serving to vary their spiral relation to the cylinder B. On rot-ating the shaft 1) the cylinder B together with the blades 10 and 11 will be caused to revolve. The blades being disposed diagonally or spirally relative to the axis of the revolving cylinder will effect a screw action of the fluid in which the blades revolve, the entrant or leading ends of the blades moving at an angle into the surrounding fluid serving to direct the fluid contacted thereby rearwardly thereby tending to pull the propeller and its attached structure forwardly.

When the propeller advances, the cone F acts to density the fluid flowing to the blades so that the latter will act on a denser volume of the fluid than otherwise. A pressure is thus built'up forward of the blades which because of the inclinations of the latter will assist in effecting rotation of the propeller.

I claim:

1. In a propeller, a hollow cylinder formed with a eircumferentially extending slot, a drive shaft on which said cylinder is mounted, axially aligned trunnions projecting diametrically from opposite sides of said shaft, blades carried on said trunnions and projecting through said slot with their outer portions protruding from said cylinder in a spiral relation thereto throughout a half convolution, and projecting flanges on said blades closing said slot.

2. In a propeller, a hollow cylinder formed with a circumferentially extending slot, a drive shaft on which said cylinder is mounted, axially aligned trunnions projecting diametrically from opposite sides of said shaft, blades carried on said trunnions and projecting through said slot with their outer portions protruding from said cylinder in a spiral relation thereto throughout a half convolution, and projecting flanges on said blades closing said slot, the outer faces of said flanges being and seating on the inner margins of said slot.

3. In a propeller, a hollow cylinder formed with a circumferentially extending slot, 2. drive shaft carrying said cylinder, axially aligned trunnions carried by said shaft, blades on said trunnions protruding diagonally through said slot with their outer portions projecting from the outer peripheryof formed on a segment of a sphere said 0 linder and each blade, extending throug out one half the-circumference of said cylinder; flanges on said blades closing said slot, and means for adjusting said blades to various positions transversely of said slot to vary the diagonal pitch thereof.

In' a propeller, a hollow cylinder formed With a circumferentially extending slot, a drive shaft carrying said 0 linder, axially aligned trunnions carried y said shaft, blades on said trunnions protruding diagonally through said slot with their outer portions projecting from the outer periphery of said cylinder and each blade extending throughout one half the circumference of said cylinder, flanges on said blades closing said slot, means for collectively adjusting said blades to various positions transversely of said slot to vary the diagonal pitch thereof, and means cooperating with said last named means to secure said blades against turning on said trunnions.

5. In a propeller, a cylinder formed with a circumferentially extending slit, a drive shaft on which said cylinder is ounted, a

plurality of blades carried by said drive shaft protruding through said slot, means for adjusting said blades to various positions transversely of said slot, and means carried by said blades closing said slot. 7

MARCELLUS EUGENE SMITH. 

